Nature of the metal-carbon contacts in end-diamido d(0) metal complexes

Folding of ene-diamido chelates in d(0) metal complexes is generally attributed to a saturating pi interaction of the metal with the central C=C linkage. A MO analysis of selected models (DFT and EHMO levels) shows that the latter interaction is negligible (negative M-C overlap populations). Moreover, a detailed analysis of the orbital interactions highlights a two-electron how from filled p, orbitals of the nitrogen atoms toward the metal consequent to ligand folding. Conversely, it is evident that the C=C pi-electron cloud is only barely affected by the contacts with the metal atom.